Obesity is associated with insulin resistance and insulin-mediated glucose metabolism occurs mostly in muscle. Lipoprotein lipase (LPL) promotes obesity by directing dietary fat into adipose tissue. These studies examine the relationship between LPL, insulin sensitivity, and muscle oxidative enzymes in obese and reduced-obese subjects. Prior to the termination of this protocol (the PI left the institution), the GCRC was involved in analyzing MRI data for determination of abdominal and femoral fat thickness, and in collecting muscle and fat biopsies.